package com.atguigu.common.utils;

import javax.crypto.*;
import javax.crypto.spec.SecretKeySpec;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

/**
 * @Author: fd
 * @Date 2021/5/12 20:46
 * @Description:
 */
public class AesUtils {

	/**
	 * 加密
	 *
	 * @param content 需要加密的内容
	 * @param password  加密密码
	 * @return
	 */
	public static byte[] encrypt(String content, String password) {
		try {
			KeyGenerator kgen = KeyGenerator.getInstance("AES");
			kgen.init(128, new SecureRandom(password.getBytes()));
			SecretKey secretKey = kgen.generateKey();
			byte[] enCodeFormat = secretKey.getEncoded();
			SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
			Cipher cipher = Cipher.getInstance("AES");// 创建密码器
			byte[] byteContent = content.getBytes("utf-8");
			cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化
			byte[] result = cipher.doFinal(byteContent);
			return result; // 加密
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		} catch (NoSuchPaddingException e) {
			e.printStackTrace();
		} catch (InvalidKeyException e) {
			e.printStackTrace();
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		} catch (IllegalBlockSizeException e) {
			e.printStackTrace();
		} catch (BadPaddingException e) {
			e.printStackTrace();
		}
		return null;
	}

	/**解密
	 * 解密的时候要传入byte数组
	 * @param content  待解密内容
	 * @param password 解密密钥
	 * @return
	 */
	public static byte[] decrypt(byte[] content, String password) {
		try {
			KeyGenerator kgen = KeyGenerator.getInstance("AES");
			SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
			random.setSeed(password.getBytes());
			kgen.init(128, random);
			SecretKey secretKey = kgen.generateKey();
			byte[] enCodeFormat = secretKey.getEncoded();
			SecretKeySpec key = new SecretKeySpec(enCodeFormat, "AES");
			Cipher cipher = Cipher.getInstance("AES");
			cipher.init(Cipher.DECRYPT_MODE, key);
			byte[] result = cipher.doFinal(content);
			return result;
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		} catch (NoSuchPaddingException e) {
			e.printStackTrace();
		} catch (InvalidKeyException e) {
			e.printStackTrace();
		} catch (IllegalBlockSizeException e) {
			e.printStackTrace();
		} catch (BadPaddingException e) {
			e.printStackTrace();
		}
		return null;
	}

	/**将二进制转换成16进制
	 * @param buf
	 * @return
	 */
	public static String parseByte2HexStr(byte buf[]) {
		StringBuffer sb = new StringBuffer();
		for (int i = 0; i < buf.length; i++) {
			String hex = Integer.toHexString(buf[i] & 0xFF);
			if (hex.length() == 1) {
				hex = '0' + hex;
			}
			sb.append(hex.toUpperCase());
		}
		return sb.toString();
	}

	/**将16进制转换为二进制
	 * @param hexStr
	 * @return
	 */
	public static byte[] parseHexStr2Byte(String hexStr) {
		if (hexStr.length() < 1) {
			return null;
		}
		byte[] result = new byte[hexStr.length()/2];
		for (int i = 0;i< hexStr.length()/2; i++) {
			int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16);
			int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16);
			result[i] = (byte) (high * 16 + low);
		}
		return result;
	}

	public static void main(String[] args) {
		String content = "210782197211110837";
		String password = "fzdtqwkj20210512";
		//加密
		System.out.println("加密前：" + content);
		byte[] encryptResult = encrypt(content, password);
		String encryptResultStr = parseByte2HexStr(encryptResult);
		System.out.println("加密后：" + encryptResultStr);


		//解密
		byte[] decryptFrom = parseHexStr2Byte("0987B5999C776EDB99CA207FCA14E45FC21FD4ECC0D0AC387129D6F32AC2B83D");
		byte[] decryptResult = decrypt(decryptFrom,password);
		System.out.println("解密后：" + new String(decryptResult));
	}


}
